Pope Francis launched his first visit to the United States with a characteristic gesture of humility on Tuesday, and sent a conciliatory message to the world's wealthiest nation about his frequent criticism of capitalism.

After a red carpet welcome by President Barack Obama at an air base near the capital, the 78-year-old Argentine headed off to Washington not in a limousine as is customary but in a modest Fiat.

Schoolchildren cheered the pontiff as his Alitalia plane landed, chanting "We love Francis, yes we do. We love Francis, how about you?"